Timothy J Swift

US Patent:

62023160, Mar 20, 2001

Filed:

Apr 14, 1998

Appl. No.:

9/059861

Inventors:

Timothy J. Swift - Gilbert AZ
John M. Hunter - Chandler AZ

International Classification:

G01B 5008

US Classification:

33503

Abstract:

A composite structure for use in a coordinate measuring machine (CMM) includes a metallic material joined to a non-metallic material, wherein each material possesses a coefficient of thermal expansion (CTE) less than or equal to 6. 1. times. 10. sup. -6 cm/cm/. degree. C. The metallic material may be INVAR, an alloy of iron and nickel, and the non-metallic material may be carbon fiber reinforced composite. Also, the metallic material may be in the shape of a space frame with the non-metallic material in the shape of stiffeners adhered to the space frame. The modulus of elasticity of the combined space frame and stiffeners is preferably greater than 140 GPa. The space frame may be a modified I-beam with reinforcing structures and mass-reducing cutouts. The stiffener may be a square tube, wherein one stiffener is adhered to each I-beam flange of the space frame. The stiffeners are ground and lapped to produce bearing tracks of high precision for air bearings to traverse.